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Formula: Ca8S5(S2O3)(OH)12.20H2O
Hydrated sulphate
Crystal System: Monoclinic
Specific gravity: 1.83 measured, 1.845 calculated
Hardness: 2
Streak: Light yellow
Colour: Orange to yellow
Luminescence: No luminescence in UV (360 nm)
Solubility: Decomposes in water, giving sulphur and a white porous residuum;
decomposes in hydrochloric acid to give sulphur and H2S; slowly
hydrolyses
in air, gradually becoming colourless with a weak bluish tint (AM 74.500-505)
Environments
Bazhenovite was originally reported as a rare, thiosulphate-containing mineral, with the chemical formula
CaS5⋅CaS2O3⋅6Ca(OH)2⋅20H2O. In 2005, however, a report was published
on a crystal from the type locality that was examined and the thiosulphate group
[S6+O3S2-]2− was not detected by either structural analysis
or spectroscopic
investigations. Either the original specimen was mis-reported, or there is a possibility that bazhenovite and the
mineral reported in 2005 represent two distinct phases differing slightly from each other with respect to the
thiosulfate content
(AM 90.1556-1562).
Localities
At the type locality, the Korkinskii coal quarry, Korkino, Korkinsky District, Chelyabinsk Oblast, Russia, bazhenovite
forms aggregates up to 1 cm in diameter, of orange to yellow bladed crystals up to 5 mm long. Associated minerals include
siderite, pyrite,
portlandite, native iron, native
sulphur, oldhamite,
troilite, pyrrhotite,
fluorite, and periclase in altered
pyritised siderite fragments in the melted
products of the old, burning coal dumps
(AM 74.500-505, HOM).
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